High-heel shank and high-heeled shoes using same

ABSTRACT

A modified shoe shank for a high-heeled shoe is described herein. The shoe shank comprises an arch support configured to provide support to a user&#39;s foot arch, a heel support connected to a rear portion of the arch support to provide support to the user&#39;s foot heel, and a front support connected to a front portion of the arch support to provide support to the ball of the user&#39;s foot. The arch support and the heel support form a rear curve having a negative curvature, and the arch support and the front support form a front curve having a positive curvature. A spring portion may be disposed proximate to the heel support wherein the spring portion is designed to reduce the impact forces communicated from the user&#39;s heel to the heel support of the shoe shank. Also disclosed is a high-heeled shoe incorporating the modified shoe shank.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/918,509 filed on Dec. 19, 2013, which is hereby incorporated by reference in its entirety.

FIELD

The present invention relates generally to high-heeled shoes and more particularly to a shoe shank for high-heeled shoes.

BACKGROUND

High-heeled shoes are very popular for their aesthetic appeal. However, high-heel shoes are typically not very comfortable, and can cause pain in a wearer's foot when worn for prolonged periods of time. The use of high-heeled shoes, and the elevation of the wearer's heel, shifts the balance of the coronal plane of a body from back to front. Due to the shift of the coronal plane from back to front, the center of gravity of the body shifts towards the ball of the foot. This change of balance demands compensation in posture by other parts of the body, causing the knees to bend slightly forward, and pushing the hips and spinal cord out of alignment. This results in an increased amount of pressure on the ball of the foot rather than the heel bone. The change of the center of coronal balance pushes the weight of the body uncomfortably onto the metatarsals, sesamoids or floating bones of the foot, instead of a natural distribution of force onto the heel bone.

While wearing a flat heel shoe or standing on a flat surface barefooted, the center of gravity of the body is along the heel bone. As a result, the maximum weight of the body is on the heel bone. Since the purpose of the heel bone is to transfer the body weight to the ground, there is minimal discomfort generated while wearing flat-heeled shoes or while standing barefooted. However, while wearing high-heeled shoes, there is a repositioning of the center of gravity and the center of gravity shifts from back to front of the body causing the ball of the foot to bear a larger percentage of the user's body weight. The weight of the body is further concentrated on the ball of the foot due to the angle, which the foot makes with the inner sole of the high-heeled shoe.

In order to address this problem, attempts have been made at redistribution of weight by means of cushioning, however as the cushioning degrades, the weight of the body gets concentrated at a single point hence providing a limited amount of weight redistribution.

Various methods for enhancing the comfort level of high-heeled shoes have been attempted, such as in U.S. Pat. Nos. 5,373,650 and 7,962,986,each of which disclose a shoe insert to reposition a user's center of gravity. However, these inserts do not fit all shoe types, and attempt to compensate for the shape of the shoe, rather than revising the shoe itself.

U.S. Pat. No. 5,782,015 describes a high-heeled shoe in which the heel seat is lowered and the toe box is raised to distribute the weight of the user back towards the heel. However, this design fails to address the foundation of the heel architecture, i.e., the heel shank, and simply changes the shape of the materials surrounding the heel shank. By addressing only the shape of the materials surrounding the heel shank and failing to address the shank itself, this solution is not easily applied to a broad range of styles of high-heeled shoes.

The solutions suggested by these patents fail to fix the root problem in the architecture of high-heeled shoes. Thus, it can readily be appreciated that there is a need for a high-heeled shoe that is designed to shift a wearer's center of gravity towards the heel of a user's foot, while being easily applied to the wide range of high-heeled shoes that are available in the marketplace.

SUMMARY

The present invention may be embodied in a shoe shank for use in a high-heeled shoe. The shoe shank comprises an arch support that is configured to provide support to a user's foot arch and extend at an upward angle with respect to the ground when the shoe shank is used in a high-heeled shoe. The arch support is designed in order to approximate the shape of the user's foot arch and in some embodiments may have a fluted portion extending along the length of the arch support. Further, the arch support has an inner arch support portion and an outer arch support portion. The inner arch support portion is raised higher than the outer arch support portion. A heel support configured to provide support to the user's foot heel is connected to the rear portion of the arch support. The heel support and the arch support form a rear curve having a negative curvature. A front support connected to a front portion of the arch support is configured to provide support to the ball of the user's foot. The front support and the arch support form a front curve having a positive curvature. Further, in some embodiments a dampening member may be disposed proximate to the heel support, wherein the dampening member is designed to reduce the impact forces communicated from the user's heel to the heel support of the shoe shank.

The present invention may also be embodied in a high-heeled shoe incorporating the shoe shank described above. The high-heeled shoe may comprise a sole having a top surface and a bottom surface, a heel proximate the rear of the sole, and the shoe shank described above positioned between the top surface and the bottom surface of the sole.

Other features and advantages of the invention should become apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF DRAWINGS

Presently preferred embodiments of the invention will now be described, by way of example only, with reference to the following drawings.

FIG. 1 illustrates the shift in the center of gravity of a body caused due to use of a conventional high-heeled shoe as compared to flat heel shoes.

FIG. 2 illustrates a modified high-heeled shoe with a modified shoe shank, in accordance with an embodiment of the present invention.

FIG. 3 provides a perspective view of the modified shoe shank of FIG. 2, in accordance with an embodiment of the present invention.

FIG. 4 illustrates the different layers constituting a sole of the modified high-heeled shoe, according to an embodiment of the present subject matter.

FIG. 5 illustrates repositioning of the center of gravity of a body wearing a conventional high-heeled shoe (2 a) and the modified high-heeled shoe of FIG. 2.

FIG. 6 further illustrates the shift in the center of gravity of a body while wearing the modified high-heeled shoe of FIG. 2.

FIG. 7 is a right-side perspective view of another embodiment of a modified shoe shank in accordance with the present invention.

FIG. 8 is a right-side view of the modified shoe shank of FIG. 7.

FIG. 9 is a front view of the modified shoe shank of FIG. 7.

FIG. 10 is a longitudinal cross-sectional view taken along the center-line of the modified shoe shank of FIG. 7.

DETAILED DESCRIPTION

The present invention discloses a shoe shank for a high-heeled shoe, wherein the shoe shank enables shifting of the user's center of gravity towards the heel bone. In one implementation, the shoe comprises a sole having a top surface and a bottom surface, a heel proximate the rear of the sole and the shoe shank placed between the top surface and the bottom surface of the sole. Further, the shoe shank may comprise an arch support, a heel support and a front support. The arch support is configured to provide support to the user's foot arch. The heel support is connected to a rear portion of the arch support and is designed to provide support to the heel of the user's foot. The front support is connected to a front portion of the arch support and is designed to provide support to the ball of the user's foot. In some embodiments, the front support, the heel support, or both may be arranged so that they are substantially horizontal with respect to the ground when the shoe shank is used in a high-heeled shoe. Furthermore, a dampening member in the form of a spring is preferably disposed proximate to the heel support. The dampening member reduces the impact forces communicated from the user's heel to the he& support of the shoe shank. FIG. 1 elaborates on the variation in the center of gravity with respect to the heel height. FIG. 2 elaborates on the correction in center of gravity of the user after using the shoe with the claimed shoe shank as compared to the conventional high-heeled shoe. FIGS. 3 through 6 elaborate on the workings of the disclosed shoe shank and the high-heeled shoe incorporating the shoe shank.

Referring now to the drawings, and particularly to FIG. 1 thereof, there is shown an illustration of the shift in the center of gravity of a body caused by use of a conventional high-heeled shoe 107 as compared to a flat heel shoe 103. As demonstrated on the left side in FIG. 1, a user wearing a flat-heeled shoe has a center of gravity 101 that is positioned over the heel bone 105. This is because the foot remains parallel to surface of the ground and, as a result, the user's legs are substantially perpendicular to the ground while wearing the flat heel shoe 103. As a result, the majority of the user's body weight is concentrated on the heel bone of the foot. The heel bone 105 is strong enough to sustain the entire weight of the body. Hence, the user is comfortable wearing the flat-heeled shoe 103.

However, as shown on the right side of FIG. 1, when a user wears a conventional high-heeled shoe 107, the foot is at an angle with the ground surface. As a result, the center of gravity 101 of the body is pushed towards the metatarsals/sesamoids, hereafter referred to as ball of the foot 109. The ball of the foot 109 is not intended to carry so much weight, and, as a result, pain is experienced by the user wearing the conventional high-heeled shoe 107 after a comparably short period of time.

FIG. 2 illustrates a modified high-heeled shoe 201 in accordance with an embodiment of the present disclosure. The modified high-heeled shoe 201 comprises a modified shoe shank 301, a high heel 303, straps 305 and a sole 307. The sole 307 has a top surface and a bottom surface. The modified shoe shank 301 is positioned between the top surface and the bottom surface of the sole 307. The sole 307 extends over the entire body of the high-heeled shoe 201 and completely covers the shoe shank 301. The high heel 303 is proximate the rear of the sole 307. The straps 305 are attached to the sole 307 and are configured to hold the foot above the sole 307. The modified shoe shank 301, along with other aspects of the modified high-heeled shoe 201, result in a shifting of the wearer's center of gravity towards the heel bone. The aspects of the modified shoe shank 301 and the modified high-heeled shoe 201 that result in shifting of the center of gravity will now be discussed in greater detail.

FIG. 3 illustrates the different components of the modified shoe shank 301 in greater detail. The modified shoe shank 301 comprises a heel support 401, an arch support 403, and a front support 405. The heel support 401 is connected to the rear portion of the arch support 403 to provide support to the heel of the user's foot. The heel support 401 and the arch support 403 form a rear curve having a negative curvature. The negative curvature provides a more natural platform for the heel of the foot to rest in place. Whereas a conventional high-heeled shoe forces a user to lean forward onto the ball of their foot, the negative curvature formed by the heel support 401 and the arch support 403 allows a user to lean back onto their heel, moving the center of gravity of the user backwards towards the heel bone.

The front support 405 is connected to the front portion of the arch support 403 such that the front support 405 provides support to the ball of the user's foot. The front support 405 and the arch support 403 form a front curve having a positive curvature. The positive curvature holds the ball of the foot at a comfortable position.

In some embodiments, the front support 405 and the heel support 401 are substantially horizontal with respect to the ground surface. However, as can also be seen in the figures, the front support 405 and the heel support 401 may deviate from horizontal and still fall within the bounds of the present invention. For example, the heel support 401 in FIG. 6 is at an angle that is slightly higher than horizontal, and the front support 405 is at an angle slightly lower than horizontal. The deviation from horizontal may be slight as shown in FIG. 6 or in some cases more substantial. Ideally, the radius of the negative curvature formed by the heel support 401 and the arch support 403, is such that it allows the user to lean back onto their heel so as to move the center of gravity of the user backwards towards the heel bone, while at the same time not being so small as to create a new pressure point between the user's arch and heel.

As described above, the heel support 401 provides support for a user's heel, while the front support 405 provides support for the ball of the user's foot. The arch support 403 is configured to provide support to the user's foot arch and is shaped to approximate the shape of the user's foot arch. The shape of the arch support provides greater support than that of a convention high-heel shank. In a more particular embodiment, the arch support 403 has an inner arch support portion 409 and an outer arch support portion 407, and is longitudinally asymmetrical. The inner arch support portion 409 is raised higher than the outer arch support portion 407 so as to approximate the arch formed in a user's foot arch. Furthermore, a fluted portion 413 may extend along the length of the arch support 403 to provide strength and rigidity to the modified shoe shank 301.

In a further embodiment, a spring portion 411, which acts as a dampening member, is disposed proximate the heel support 401. The spring portion 411 reduces the impact forces communicated from the user's heel to the heel support 401 of the shoe shank 301. The spring portion 411 may be formed integral with the heel support 411 and dampening may be provided at the spring portion 411 by a combination of the shape of the heel support, the thickness of the heel support, and the material used in the heel support 401. In FIG. 6, the spring portion 411 comprises an arched area that is intended to flex when substantial force is exerted by the user's heel. The flexing of the spring portion 411 absorbs some of the force communicated by the user's heel and provides a dampening effect. The spring portion 411 adsorbs the forces exerted on the user's foot when the user is walking, taking steps, standing, jumping or performing any action in which a substantial force is exerted on the user's foot. The dampening property of the spring support absorbs some of the force acting thereon and less force is imparted on the user's foot. In other embodiments, a gel material, such as a silica gel, thermoplastic elastomer (TPE), and/or thermoplastic polyurethane (TPU) or a similar compound may be used to cover the spring portion 411. In still other embodiments, the dampening member may comprise a layer of gel material, such as a silica gel, TPE and/or TPU or similar compound disposed in the sole 201 above the heel support 401. The viscoelastic properties and thickness of the gel layer should be such as to provide the desired dampening properties for the dampening member.

The modified shoe shank 301 may comprise ballistic grade plastics, high carbon steel materials, carbon fiber reinforced plastic, or other high strength materials that are able to support a user's weight.

FIG. 4 provides a close-up view of the sole 307 of the modified high-heeled shoe 201. The sole 307 comprises a top surface 601, silicone gel layer 603, a sorbathane layer 605, a leather outsole layer 607, and a urethane tread layer 609. The shoe shank 301 is positioned between the top and bottom surfaces of the sole 307. In FIG. 4, the modified shoe shank 301 is positioned between the sorbathane layer 605 and the silicone gel layer 603. The combination of all these layers, along with the novel shape of the modified shoe shank 301, improve the shock absorbing and weight distribution properties of the modified high-heeled shoe 201. The overall shock absorbing capacity of the shoe is enhanced by 15 to 20% with this combination of layers when compared to a conventional sole.

In one embodiment, the urethane tread layer 609 acts as the outermost layer of the sole and protects the leather outsole layer 607 from external wear and tear. The urethane tread layer 609 is designed to add traction and additional shock absorbance. The top surface 601 lies against the skin of the foot and may be formed of a high-friction material so as to prevent slipping of a user's foot within the shoe. The top surface 601 may be flocked with cotton or trace silver as an antimicrobial agent. The silicone gel layer 603 along with the sorbothane layer 605 provide a smooth surface for the foot to rest and enables greater distribution of weight across the heel support, arch support, and front support so that the weight of the user is not concentrated on the ball of the user's foot.

FIG. 5 illustrates repositioning of a user's center of gravity when wearing a modified high-heeled shoe having a modified shoe shank, in accordance with an embodiment of the present invention. The left side of FIG. 5 presents a convention high-heeled shoe. While wearing the conventional high-heeled shoe 107, the center of gravity 101 is along the ball of the foot. The angle θ° represents the angle of the leg 505 from the normal 500, drawn perpendicular to the ground, while wearing the conventional high-heeled shoe 107. As seen on the right side of FIG. 5, the angle θ′ a represents the angle made by the leg 505 with the normal 500, drawn perpendicular to the ground, while wearing the modified high-heeled shoe 201 having a modified shoe shank.

It can be seen in FIG. 5 that the angle of the user's leg when wearing the modified high-heeled shoe (θ′) is smaller than the angle of the user's leg when wearing the convention high-heeled shoe)(θ°). The modified geometry of the modified high-heeled shoe 201 causes the center of gravity 101 to shift towards the heel bone 105 and the weight of the body is concentrated more towards the heel bone 105, as compared to the conventional high-heeled shoe.

FIG. 6 further illustrates the variation in the center of gravity 101 of a body while wearing the modified high-heeled shoe 201 of height h₃. ‘O’ represents the line of center of gravity 101 while wearing a conventional high-heeled shoe. Lines x₁, x₂, x₃ represent the user's center of gravity 101 while wearing a modified high-heeled shoe 201 having a modified shoe shank 301 for different heel heights H (h₃, h₂, h₁). As the height of the heel 303 increases from h₁ to h₃, the center of gravity moves forward from x₃ to x₁ However the center of gravity is considerably closer to the heel bone as compared to the position of center of gravity ‘O’ in the case of a conventional high-heeled shoe 107 of height h₃. The shift in the center of gravity 101 is substantially provided by the shape of the modified shoe shank 301, as the arch support 403 of the shoe shank 301 is shaped to provide greater support to the arch of a user's foot, and the heel support 401 provides an appropriate platform for the heel to rest, allowing the user to shift their weight backwards towards their heel bone, and away from the ball of their foot.

In one exemplary embodiment, when the height ‘H’ of the heel 303 measures between 2 to 5 inches and the user is in a standing position, the amount of weight placed on the ball of the user's foot is reduced by at least 5% to 20% as compared to the weight distribution in a conventional high-heeled shoe of the same height.

FIGS. 7-10 illustrate a modified shoe shank 601 in accordance with another embodiment of the present disclosure. The shoe shank 601 can be used substituted for the shoe shank 301 in high-heeled shoe 201. Accordingly, like items in shoe shank 601 are designated with same reference numbers in order to avoid duplicative description.

As used in this specification and claims, the term “for example”, “for instance”, “such as” and “like” and the verbs “comprising”, “having”, “including” and theft other verb forms, when used in conjunction with a listing of one or more components or other items, are to be construed as open-ended. Meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation. It should also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

Although the invention has been disclosed with reference only to the presently preferred embodiments, those of ordinary skill in the art will appreciate that various modifications can be made without departing from the invention. Accordingly, the invention is defined only by the following claims. 

What is claimed is:
 1. A shoe shank for use in a high-heeled shoe, the shoe shank comprising: an arch support that is configured to provide support to a user's foot arch and that extends at an upward angle with respect to the ground when the shoe shank is used in a high-heeled shoe, the arch support having a longitudinally asymmetrical shape that approximates the shape of the user's foot, wherein the arch support includes an inner arch support portion and an outer arch support portion, the inner arch support portion being raised higher than the outer arch support portion; a heel support connected to a rear portion of the arch support to provide support to the heel of the user's foot, wherein the heel support and the arch support form a rear curve having a negative curvature; and a front support connected to a front portion of the arch support to provide support to the ball of the user's foot, wherein the front support and the arch support form a front curve having a positive curvature.
 2. The shoe shank of claim 1, wherein the front support is substantially horizontal with respect to the ground.
 3. The shoe shank of claim 1, wherein the front support, the heel support or both are substantially horizontal with respect to the ground.
 4. The shoe shank of claim 1, wherein the arch support further comprises a fluted portion extending along the length of the shoe shank.
 5. The shoe shank of claim 1, wherein the shoe shank is made by using at least one of the materials selected from a group of ballistic grade plastics, high carbon steel materials, or carbon fiber reinforced plastic.
 6. The shoe shank of claim 1, wherein a spring portion disposed proximate to the heel support, wherein the spring portion is designed to reduce the impact forces communicated from the user's heel to the heel support of the shoe shank.
 7. The shoe shank of claim 6, wherein the spring portion is formed integral with the heel support and a dampening force is provided by a combination of: the shape of the heel support, the thickness of the heel support, and the material used in the heel support.
 8. The shoe shank of claim 2, wherein the radius of the negative curvature formed by the heel support and the arch support is not so small as to create a new pressure point between the user's arch and heel.
 9. A high-heeled shoe comprising: a sole having a top surface and a bottom surface; a heel proximate the rear of the sole; and a shoe shank positioned between the top surface and the bottom surface of the sole, the shoe shank comprising: an arch support that is configured to provide support to a user's foot arch and that extends at an upward angle with respect to the ground, the arch support having a longitudinally asymmetrical shape that approximates the shape of the user's foot, wherein the arch support includes an inner arch support portion and an outer arch support portion, the inner arch support portion being raised higher than the outer arch support portion; a heel support connected to a rear portion of the arch support to provide support to the user's foot heel, wherein the heel support and the arch support form a rear curve having a negative curvature; a front support connected to a front portion of the arch support to provide support to the ball of the user's foot, wherein the front support and the arch support form a front curve having a positive curvature.
 10. The high-heeled shoe of claim 9, wherein the front support is substantially horizontal with respect to the ground.
 11. The high-heeled shoe of claim 9, wherein the front support, the heel support or both are substantially horizontal with respect to the ground.
 12. The high-heeled shoe of claim 9, wherein the arch support further comprises a fluted portion extending along the length of the shoe shank.
 13. The high-heeled shoe of claim 9, wherein the shoe shank is made by using at least one of the materials selected from a group of ballistic grade plastics, high carbon steel materials, or carbon fiber reinforced plastic.
 14. The high-heeled shoe of claim 9, further comprising a dampening member disposed proximate to the heel support, wherein the dampening member is designed to reduce the impact forces communicated from the user's heel to the heel support of the shoe shank.
 15. The high-heeled shoe of claim 14, wherein the dampening member comprises a spring formed integral with the heel support and a dampening force is provided by a combination of: the shape of the heel support, the thickness of the heel support, and the material used in the heel support.
 16. The high-heeled shoe of claim 14, further comprising a gel material that covers the spring.
 17. The high-heeled shoe of claim 16, wherein the gel material comprises silicone gel.
 18. The high-heeled shoe of claim 9, wherein the dampening member comprises a layer of gel material disposed in the sole above the heel support.
 19. The high-heeled shoe of claim 9, wherein the heel measures between 2 to 5 inches.
 20. The high-heeled shoe of claim 19, wherein the radius of the negative curvature formed by the heel support and the arch support is not so small as to create a new pressure point between the user's arch and heel.
 21. The high-heeled shoe of claim 9, wherein when the user is in a standing position, the amount of weight placed on the ball of the user's foot is reduced by at least 5% compared to the same high-heeled shoe implementing a conventional high-heeled shoe shank.
 22. The high-heeled shoe of claim 21, wherein the amount of weight placed on the ball of the user's foot is reduced by at least 10%.
 23. The high-heeled shoe of claim 21, wherein the amount of weight placed on the ball of the user's foot is reduced by at least 20%. 